All polyethylene shotshell case

ABSTRACT

A shotshell case entirely of injection molded high molecular, high density polyethylene. The case having a base wall with a base wad thereon in overlying position, or having an integral base wad and base wall.

United States Patent 1191 Herter 1 1 Mar. 27, 1973 [541 ALL POLYETHYLENE SHOTSHELL 3,517,617 6/1970 Hall ..102 43 P CASE 3,590,740 7/1971 Herter ..102/43 P [7 Inventor: George Herter, Was/sea, Minn- FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Herters, Inc., Waseca, Minn- 832,561 4/1960 Great Britain ..102/43 P 22 Filed: J 11 911,258 3/1946 France ..102/43 P 1,140,147 2/1957 France ..102/43 P [21] Appl. No.: 105,410

Primary Examiner--Robert F. Stahl 52 us. c1. ..l102/43 P, 102/42, 102/44, Attorney-Williamson. Palmatier & Bains, Dale 102/95 Palmatier, Herman H. Bains and Malcolm L. Moore [51] Int. Cl ..F42b 5/30 [58] Field of Search 102/42, 42 c, 43, 43 P, 43 c, ST ACT 102/44 95 A shotshell case entirely of injection molded high molecular, high density polyethylene. The case having [56] References C'ted a base wall with a base wad thereon in overlying posi- UNITED STATES'PA'TENTS tion, or having an integral base wad and base wall. 3,171,350 3/1965 Metcalf et a1. ..102/43 P 1 Claim, 7 Drawing Figures .11 -1' l 1' il. \h i 0 I l\ h wi l 11 52:; 1 1 1 20 w l i l ALL POLYETIIYLENE SHOTSHELL CASE Previously, no one has successfully made a shotshell case integrally from polyethylene suitable to withstand the shock of firing of the shotshell, or with the ability to be reloaded several times so as to withstand the several successive shocks due to firing of the primer and powder charge in the shotshell. Outer metal jackets, metal base walls, and silver apparatus have been used with polyethylene tubular walls to produce plastic shotshell cases, and some shotshell cases have been successfully manufactured from extremely high tensile plastics such as polycarbonates.

BRIEF SUMMARY OF THE INVENTION An all-plastic shotshell case formed by injection molding of polyethylene, preferably high molecular, high density polyethylene which has high tensile strength. The shotshell case may be repeatedly loaded and fired, as many as 15 to 20 times without critical damage to the shotshell case. The shotshell case may have a relatively thin transverse base wall and a separate base wad of low density polyethylene, fitting snugly into the baseend of the shotshell case. Alternately, the shotshell case may have an integral base wad, formed into the transverse base wall of the case. The combined base wad and base wall may have a metal rivet defining a metal jacket or periphery of the primer pocket and affixed to the base wall. The shotshell case may be adapted for a star crimp or may be rolled over for a separate closure wad.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view partly broken away, and illustrating a'shotshell case formed according to the present invention.

FIG. 2 is an enlarged transverse section view through the base of the shotshell case.

FIG. 3 is an elevation view of the shotshell case, partly broken away for clarity of detail, and shown, diagrammatically inserted into the shotshell chamber of a shotgun barrel.

FIG. 4 is an elevation view of the shotshell case, but modified slightly compared to that illustrated in FIGS. 1 3 and showing the shotshell case employing a separate closure wad.

FIG. 5 is an enlarged transverse section view showing a modified form of the invention.

FIG. 6 is an enlarged detail transverse section view showing a modified form of the invention using a separate base wad. I 7

FIG. 7 is an enlarged detail transverse section view showing a different form of base wad than used in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION One form of the invention is illustrated in FIGS. 1 3.

The shotshell case 10 is formed by injection molding of polyethylene, preferably high molecular, high density polyethylene with high tensile strength. This material has not previously been used as an injection molding material, but is primarily an extrusion material, and has an original consistency approximately like putty. The tubular case wall 11 is, in this form, formed with a closure portion I2 which, when the shotshell is loaded with shot and powder charges, will be folded inwardly in a star crimp to retain the other charges in the shotshell case. The tubular wall 11 also has sealing rings 13 at the exterior periphery and adjacent the mouth portion of the case so as to prevent powder gases from passing rearwardly along the shotshell case when the shotshell is fired in the barrel of a shotgun. These rings 13 will seal against the barrel of the shotgun during firing.

The case 10 has a base wall 14 with a thickness exceeding the thickness of the tubular wall 11 by several multiples. In the form illustrated, the base wall 14 has a thickness approximately six to eight times as great as the thickness of the tubular wall 11. As a result of this added thickness of the base wall, the base wall serves as the base wad of the shotshell case and thereby is considered a combined base wall and base wad. No additional wad at the base of the shotshell case is necessary, and the powder charge is inserted directly over the combined base wall and base wad 14 illustrated in FIG. 2. The combined base wall and wad 14 has a primer opening 15 formed axially therein and also provided with a shoulder 15a at the outer periphery to receive the small rim of the primer. The primer P is illustrated in FIG. I, inserted into the primer opening 15. The combined base wall and wad I4 defines peripheral ribs 16 at the periphery of the primer opening for the purpose of very tightly gripping the primer P and for sealing between the primer and the combined base wall and wad to prevent any powder gases from moving rearwardly along the primer during ignition of the powders in the shotshell.

The combined base wad and wall 14 also has an annular recess 17 spaced outwardly from the primer opening 15 and at the inner surface of the combined base wall and wad 14 to permit insertion of a suitable annular tool for crimping the periphery of the combined base wall and wad 14 against the primer P in the opening 15 after the shotshell case has been used several times so that the tight sealing relationship between the primer and the combined base wall and wad 14 can be maintained through many reloadings of this shotshell case. It has been found that at least I5 to 20 reloads can be obtained through the use of this shotshell case 10 without any serious damage to the shotshell case of the type which might affect the accuracy of the firing or cause a safety hazard.

The transverse base wad and wall 14 also defines a peripheral flange 18 at the outer periphery for use in ejecting the spent shotshell case from the barrel B of the shotgun, and after the breech bolt 0 is withdrawn.

In FIG. 4, the modified form of shotshell case 10 has the tubular case wall 11' formed somewhat shorter than the comparable tubular case wall 11 of FIG. 1, and a top closure wad 19 is employed to retain the shot charge S in the case. The top wad 19 is retained in position by a simple rollingor slight crimping of the case wall 11 at lla.

In the form of the polyethylene shotshell case indicated by numeral 10a in FIG. 6, the transverse base wall 14 has a thickness on the same order of magnitude as the tubular case wall 11", but it will be observed that the base wall 14' is about twice the thickness of the tubular case wall. A separate base wad 20 is formed to the exact shape of the internal periphery of the case wall 11" and the shape of the base wall 14, and the wad 20 has a primer opening 21 and a flash opening 22, both aligned with the primer opening in the transverse base wall 14. The base wad has a large approximately hemispherical recess 23 therein and for the purpose of receiving the powder charge of the shotshell, and maintaining the powder charge in front of the primer and flash opening 22. The base wad 20 has a plurality of exterior peripheral ribs 24 in a sawtooth configuration for engaging and sealing against the inner periphery of the tubular case wall 11 upon ignition of the powder and primer on firing of the shotshell.

In FIG. 6, the primer will engage the periphery of the primer opening 15' in the base wall 14' and will engage the periphery of the primer opening 21 in the base wad 20. Preferably the base wad 20 is formed of highly resilient low density polyethylene and the base wad will grip the primer very tightly at the opening 21 so as to retain the primer in the shotshell formed from the case. The base wad 20, in this form, will absorb a great proportion of the shock of the firing of the'primer, and due to the resiliency of the base wad 20, the shotshell case is unaffected by the shock of explosion of the primer.

In the form of the invention illustrated in FIG. 5, the shotshell case 10b has a combined transverse base wall and base wad 14a similar to that illustrated in FIG. 2, and formed integrally of the tubular case wall 11a. The primer opening 151: in the combined base wall and wad 14a is provided with a metal jacket 25 surrounding the entire periphery of the primer opening and extending substantially throughout the length thereof. The metal jacket 25 is crimped at its ends as at 25a so as to tightly grip the combined base wall and wad 14a and be permanently affixed thereto. The primer P will be received in the metal jacket 25 and be tightly gripped thereby to be retained in the combined base wall and wad 14a so as to receive the first impact of the shock of explosion of the primer upon firing of the shotshell, and as to seal against the entire periphery of the primer to retain the primer and to prevent any powder gases under high pressure from passing rearwardly along the primer and through the combined base wall and wad 14a.

The form illustrated in FIG. 7 is very similar to that illustrated in FIG. 6 with the exception that the separate base wad 26 has a smooth outer periphery. The wad 26 bears snugly against the inner periphery of the tubular case wall and against the transverse base wall of the base 10.1. The separate base wad 26, is also low density highly resilient base wad overlying the base wall to absorb a great proportion of the shock due to the explosion of the primer upon firing of the shotshell. The transverse base wall may have a thickness exceeding the thickness of the tubular case wall by several multiples so as to provide a combined base wall and base wad into which the primer is mounted and over which the powder charge of the shotshell is inserted. The combined transverse base wall and base wad may be provided with a metal jacket at the periphery of the primer opening to engage, retain and seal against the entire periphery of the primer and to absorb the initial shock of the explosion of the primer upon firing of the shotshell.

What is claimed is:

l. A shotshell case comprising:

a tubular case wall;

a transverse base wall formed integrally of the tubular case wall and having a primer opening therein and also defining an outer peripheral flange projecting outwardly of the tubular wall, the integral tubular and base walls being formed integrally of each other and in one piece with each other of high molecular, high density polyethylene;

a separate base wad within the tubular case wall and overlying the transverse base wall, said separate base wad being formed of highly resilient polyethylene with substantially better shock absorbing characteristics than the high molecular, high density polyethylene of the tubular case wall and integral base wall, said separate base wad having a primer opening and a flash hole aligned with the primer opening of the base wall, and a primer in the aligned primer openings of the base wall and separate wad and said primer engaging both the base wall and the wad, the separate base wad gripping the primer and retaining and holding the primer in the aligned primer openings and absorbing the shock of firing the primer without permitting significant localized transfer of the shock from the primer into the high molecular, high density transverse base wall of the case. 

